Is fuel (unburned) coming out of the muffler? When you say it "tries to start" do you mean that it fires somewhat but never really starts?
Have you looked at the main jet adjustment on the carb? Did you clean that when you cleaned the carb?
Have you looked at the points? You might have to remove the flywheel (may be very difficult if it hasn't been off in 30 years
) to get to them.